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A new experimental set-up is presented for studying single domain wall propagation in cylindrical amorphous Co72.5Si12.5B15 wire with helical anisotropy created by simultaneous application of tensile and torsion stresses. It is shown that conditions may be created for propagation of a single domain wall driven by electric current (circular magnetic field) in this type of sample. Even with constant electric current the wall velocity is not constant along the wire, probably due to the presence of inhomogeneities. The average wall velocity determined from the experiment is a linear function of the driving electric current, from which the domain wall mobility can be determined. Its magnitude is much higher than the mobility calculated for the model of a planar domain wall between circular domains. The axial component of magnetization is not equal to zero in wire with helical anisotropy. The balance between magnetostatic energy and domain wall energy can cause the domain wall to have non-zero axial length, and this may result in the increase in the domain wall mobility. [ABSTRACT FROM AUTHOR]

Circular magnetization reversal in cylindrical amorphous wire Co72.5Si12.5B15 with negative magnetostriction constant under applied tensile stress was investigated. Hysteresis loops of axial magnetization and circular magnetic flux showed presence of helical anisotropy with slight deviation from the circular direction. Circular magnetization reversal was studied using rectangular electric current pulses. Critical electric current (circular magnetic field) under which circular magnetization did not change with application of long current pulses was experimentally determined. If a single boundary (domain wall) between circular domains was created, then linear time dependence of circular magnetization changes versus length of current pulse of constant magnitude was observed. It is probable that the circular magnetization reversal was due to propagation of a single domain wall. Based on this assumption, domain wall velocity was determined. Linear dependence of domain wall velocity versus current magnitude was observed. The slope of this dependence is in good agreement with theoretical predictions based on eddy-current damping. In conclusion, it appears that experiments with a single domain wall are possible in wires with a high value of negative magnetostriction. [ABSTRACT FROM AUTHOR]

Domain wall dynamics in magnetic bistable glass-coated microwire under the influence of temperature was studied. The results of the experiment which can provide information about propagating domain wall geometry and its changes are presented. The measurements were performed on a Fe77.5Si15B7.5 microwire with unidirectional effect. Shortening of the domain wall with applied magnetic field was observed. It was observed that also decrease in temperature resulted in the domain wall shortening. The reason for this is that the decreasing temperature changes magnetoelastic anisotropy and amplifies the stresses in microwire induced during the manufacturing process. The observed behaviour is stronger for a slow domain wall in domain wall propagation. [ABSTRACT FROM AUTHOR]

A new experimental method for studying single domain wall (DW) dynamics in bistable microwires is presented. It provides new possibilities to study the dynamics of a domain wall moving in a region of rapidly-changing magnetic field. When the moving DW is forced to change its parameters in a very short time, the corresponding changes in velocity are different for rapid increase and decrease in field strength. Experimental v(x) dependences are compared with theoretical ones which correspond to the case when a DW moves with no inertial effects, or when the DW has enough time to adapt to the field in which it moves. The results obtained support the idea that a DW in bistable microwires is not a solid object, but changes its parameters (e.g. wall velocity) depending on the magnetic field applied. [ABSTRACT FROM AUTHOR]

Domain wall velocity versus applied magnetic field was measured at different temperatures in a glass-coated Fe77.5Si15B7.5 microwire. Measurement of velocities under four different conditions confirmed the presence of unidirectional effect in the domain wall propagation. The experimental results are interpreted using an elastic domain wall model. This explains the non-linearity of domain wall velocity versus applied magnetic field dependences as well as the wall shape transformation in a low field region, and finally provides an additional reason why wall velocity decreases with decreasing temperature. [ABSTRACT FROM AUTHOR]